Probably the three most striking characteristics of tuberculosis as seen in man at postmortem are its predominant pulmonary localization, its extension bronchogenically by aspiration in the lung, and evidences of its variegated hematogenous dissemination. The predominant pulmonary disease has been attributed in the past to the importance, in the majority of the cases, of the respiratory tract as the route of infection in tuberculosis 1 and to the filtering action of the lungs, supposedly called into play frequently, especially in infancy and childhood, when infection is believed to occur through the alimentary tract. 2 In tuberculosis, especially in childhood, the lymphatic system has been considered to assume importance, 3 and Krause, 4 on the basis of extensive studies in the guinea-pig and rabbit, considers intrapulmonary differences of lymphatic tissue, blood supply and lymph flow decisive in determining the characteristic differences of pulmonary involvement in these two species. Deposition of the